Gold concentrator



Sept. 23, 1941. RF STEWART GOLD CONCENTRATOR Filed May 23', 1958 ZSheets-Shet'l.

57 War} Sept. 23, 1941. EW 2,256,504 7 GOLD CONCENTRATOR Filed May 23, 1938 2 Sheets-Sheet 2 Patented Sept. 23, 1941 GOLD ooucsn'rasron Frank 1. Stewart, Salt Lake City, Utah Application May 23, 1938, Serial No. 209,506

4} Claims.

My invention relates to the extraction of gold and like heavy materials and has for its object to provide a new and efiicient machine for gathering such metals into a common receptacle and discharging the balance of the material or dress out of another part of the machine.

It is common knowledge that the hand operated gold pan which has been used by placer miners for centuries oiiers the most effective means of separating free gold and similar metals from the material in which it is deposited. My invention provides a mechanical means of accomplishing the same results as it simulates and duplicates the combined rocking and circular motion which an experienced gold panner uses in panning gold from sand or gravel. And it has the further feature that instead of using a single pan as does the gold panner it uses a series of pans thus producing the same effect as multiple panning by the hand process.

A further object of my invention is to provide a gold collector and concentrator which is highly eiicient and which will recover very fine or thin flour gold from gravels which are commonly lost under present methods. This is accomplished by keeping the gold or concentrate containing values covered with water at all times and by keeping the water and materials to be treated in a circular motion at all times during its passage through the machine.

The gold bearing material is subjected to a fine spray of water at the point where it enters the machine and continuously thereafter while it is in the first or upper pans through which the material passes and this has the effect of settling all of the flower and fine gold to the bottom thus preventing it from floating off as is the case with other machines for this purpose.

This device is essentially pertinent to be used on crushed ores, mill tailings, and free gold in Figure 2 is an enlarged diametrical section of one of my collector pans.

Figure 3 is a plan view of the trough with the screen or perforate cover removed.

Figure 4 is an end view of Figure 5.

Figure 6 is a sectional View of a manner of connecting the trough to the eccentric showing a flexible ball connection.

Figure 7 is a view of a single pan device for prospectors or small operations.

in the drawings I have shown my trough as A supported from a suitable framework B. The trough A consists of a plane surface '5 having one end S inclined for a feeding trough and which will hereafter be called the feed end of the device. The discharge end l is open for full discharge or the material therefrom.

The trough A has vertical sides 8 and 9 extending from end to end to form an elongated trough through which the material being treated is passed. Extending vertically from near each end of the sides 8 and 9 of the trough A are adjustable cables or chains In and H. The top ends of the cables are secured to. cross pieces iii of the framework B with the distance between the top ends of the chains Ill and H less than the width of the bottom ends when they are attached to the trough.

The length of the cables is so adjusted that with the base of the frame B in a'horizontal position the chain H1 is shorter than the chain ll thereby supporting the trough A on an incline with the feed end higher than the discharge end as shown in Figure 1. Extending outwardly to the vertical posts [4 of the framework B are springs 55, one end of which is attached to the sides 5 and 9 and the other end to the posts I' l. These springs assist the chains to support the trough and to keep it under spring tension thus smoothing out vibration when the trough is in operation.

In the bottom of the trough A are placed one \r more rows of round holes to which are attached, on the underside of the trough, the gathering pans D.

These pans D are fixed to the bottom 5 of the trough A by some rigid meanssuch as bolts or clamps or may be formed as an integral part thereof by stamping or welding.

The annular side walls ofthe pans D shown as it are slanting and that side I! .of the pan which is toward the discharge end of the trough A is shallower than the opposite side l8 so that the apex of the angle formed by the sides It and the bottom of the pans D is lower on the'feed side of the pan than is the apex of the angles formed by the side I? and the bottom IS on the discharge side of the pans thus collecting the gold in the lowest part of the pan which is toward the feed end. When so formed the feed side l8 of each pan is longer than the discharge side H and this places the bottom IQ of the pan on an angle to the surface of trough A.

All of these pans are alike in form and each is provided with a flange or lip across the discharge side of the opening in which the pan top is an integral portion thereof, this lip 26 acting to retain the fines in the pan during the operation of the device.

In the drawings I have shown the device as made with two longitudinal rows of pans E and F although I do not limit the number of rows to two. The two pans heading each row on the feed end namely El and Fl are provided with means in the bottom thereof through which the concentrates may be drawn continuously which means consist of a small port or opening 22 controlled by a plate valve 23 pivotally attached to the bottom of the pan by a pivot pin 24. A drain cook or other suitable valve may be used for this purpose if desired.

A cross trough 25 collects the material which settles through the port 22 and drains it off into a receptacle on one side as the concentrates.

Along the entire top of the trough A I provide a screen or perforated cover G, said cover having that portion adjacent to the feed end formed of an open mesh screen or perforated plate to allow the material which is smaller than the opening in the screen to pass therethrough and to cause the larger particles of the material to travel on down the upper surface of the cover to the discharge end.

To be sure that no large nuggets of gold escape in the large material the discharge end of this cover is provided with two pans 26 to catch such nuggets and hold them for recovery at a later time after the run has been completed. These two pans 26 are similarly formed and placed as pans D. The cover G is supported from the sides a l and 8 of the trough A by suitable brackets 21.

The material is fed into the inclined end 6 of the trough A from a feed hopper or feed trough 29 supported on standards 30 and the source of the material above the trough is not shown and may be any suitable manner of feeding the material into the feed trough.

Longitudinally of the entire machine I provide a pipe 3| with the end near the feed end of the trough turned down and carrying a nozzle 32 to forcibly spray the material in the feed trough with a spray of water to start the first step in my process of recovering the gold.

Directly above the trough A I provide ports 33 in the pipe 3|, as shown in the drawings, by means of which a continuation of the spray on the material is obtained as it is passed over and through the perforated end of the cover G. This spray also aids in driving the fine gold down into the material and forcing it through th openings in the cover and onto the trough and the velocity of the spray may be controlled, depending upon the material being treated.

If only fine material is being run the cover G may be removed and the machine operated with- '7 out it and the spray of water then diminished in force.

Across the bottom of the trough A near the center I provide a bracket 35 which is provided with a depending stub shaft 316. The end of this shaft passes through a wheel 31 with the shaft 36 eccentric from the center of the wheel. The wheel 3! is provided with several holes or slots therein of different distances from the true center of the wheel to allow for adjustment of the throw of the shaft 36 and consequently to vary the amount of movement transmitted to the trough A.

The shaft 38 on the wheel 3! is mounted and carried in a bearing bracket 39 and the lower end of this shaft carries a bevel gear 40 which meshes with a like gear 4| mounted on a drive shaft 42. The shaft 42 is driven by a sheave wheel 43, a bolt 44 and a motor 46 with a belt operating on the sheave wheel 45 of the motor. It will be seen that the motor drives the shaft 42 which in turn drives the shaft 38 and the wheel 31 which in turn transmits to the entire trough A a circular motion so that any point of the trough as the center of each of the pans l6 travels in an approximate circle. It will be likewise noted that a rocking motion is transmitted to the trough A in a transverse direction due to the manner in which the trough A is supported by the chains l0 and I l. Likewise this action imparts to the material and water as it passes down over the trough A a circular and rocking motion thus causing it to enter either pan El or pan Fl. This combined circular and rocking motion causes the gold in the material to settle to the bottom of the pans and causes the tailings to move down the trough into the next lower pan where any gold which may be carried over from the first row of pans settles to the bottom and in like manner the material passes through each of the succeeding pans and finally out of the discharge end of the trough A.

The springs l5 are provided to smooth out the action of the trough when it is loaded with material being treated, therefore eliminating all jerky motion of the trough.

The material is fed into the feed trough 29 and on to the cover G.

A spray of water from the nozzle in the end of the pipe strikes the gravel from the top as it passes down through the feed trough forcing the gold to the bottom of the material. Thus, when the material passes over the cover G the gold will pass through the openings and on to the trough A. The water spray continues to drive down the gold and this is particularly true of the fine or flour gold. The material falling down on to the trough A receives a circular and rocking motion and passes into and over the first two pans El and Fl where the greatest portion of the gold is settled into the bottom of the pans. This circular and rocking motion which is transmitted to the materials to be treated, they being already mixed with water, prevents the materials from compacting and permits the continuous settling of the gold and other values to the bottom of the pans.

The lip 20 also prevents the gold from passing out over the discharge side of the pans.

As the material continues to drift or move down the inclined surface 5 of the trough A it passes through each of the succeeding rows of pans so that by the time the material has reached the discharge end of the trough, the entire values have been recovered and only the tailings are discharged.

The fines and concentrates from the two top pans 6 pass through the ports in the bottom when they are open thus discharging the concentrates into the cross trough and thence to a suitable container.

Finally when the run has been completed and the pans are cleaned, the concentrates may be again run through the machine using an amalgam in the pans to more completely concentrate the gold from other heavy materials which may be retained in the concentrates.

My machine is especially well adapted to recover very fine or flour gold such as is found in many localities. The sprays of water above the pans in trough A have the effect of driving this fine or flour gold to the bottom of the pans where it is caught and held in the black sand and concentrates, and by using multiple units of the device as described a large volume of material may be treated.

In Figure 7 I have shown a single pan unit with the pan shown as K supported from a tripod support 59 by flexible chains or cables with the support eyes 52 of the cables spaced inwardly from the outer diameter of the pan so that when the pan is moved into a circular motion it will also receive a tilting motion.

A trough 53 supplies material into the pan and a pipe spray 54 supplies water spray under pressure onto the incoming ore while the material in the pan is treated constantly to water spray by the pipe spray 55. Either or both of which pipes sprays may be provided with control valves if and when desired.

Centrally under the pan I provide a power unit consisting of a train of bevel gears 55 driven by a shaft 51 and transmitting motion to a vertical shaft 58 which shaft carries a wheel 59 and eccentric shaft 60. The top end of the shaft 60 is shown as made round, as shown in dotted lines, and this ball fits into a cylinder 6|, which cylinder is mounted medially on the bottom of the pan. Thus, when the shaft 57 is rotated, which in this instance is shown as by a crank 62, the train of gears is rotated and the wheel 59 rotated. This causes the eccentric shaft to move in a circular path and which transmits motion to the pan.

Having thus described my invention I desire to secure by Letters Patent and claim:

1. In a device of the class described, the combination of a plurality of pans having slanting sidewalls with one side deeper than the other; a common trough in which said pans are set with the top 01 the pans on the same plane as the trough surface; a lip across the lower, shallower edge of said pans; flexible means to support said trough; spring means to hold the trough from jerky motion; and means to transmit a circular motion to said trough and pans.

2. A device of the class described. comprising a trough having a plurality of tilted pans formed in the bottom surface thereof, some of said pans having means to drain off concentrates from the bottom of the pan means to supply water over the material being fed into said trough and over said pans means to support said trough from above by flexible members to permit a circular motion of said trough and pans; and means by an adjustable eccentric under the center of said trough to transmit a circular motion to said trough.

3. A device of the class described, comprising a trough having a plurality of pans formed in the bottom surface thereof, said pans being formed with the apex or the angle between the side and bottom of the pans, on the feed side of the pans, lower than the apex of angle between the side and bottom of the pans at the discharge side of said pans; and means to transmit a circular motion to said trough and pans so that any given point in the trough will describe a complete circular motion.

4. A device of the class described comprising a trough having a plurality of pans formed in the bottom surface thereof, said pans having that side toward the feed end of the trough deeper with the bottom of the pan on a level at an angle to the bottom of the trough; a lip formed around the upper perimeter of the shallower side or discharge side of each pan; means to suspend said trough flexible from a suitable framework with the feed end of the trough higher; means by a slide valve in the bottom of the two upper end pans to permit removal of the Valves therefrom; a trough in which said values are caught; a transversely mounted cross piece under said pan; an eccentric mounted under said cross piece with a stub shaft connecting the eccentric with the cross piece; means to transmit rotation to said eccentric; a perforated pan mounted over I the top of said trough the full length thereof to grade the material being fed into the device; a longitudinal water feed pipemounted to transmit fine forceful spray of Water onto the material passing over said perforated pan to drive the values down into the trough.

FRANK P. STEWART. 

